How many meters does it take to capture a full-body portrait of a 170cm tall person using a Nikon D7200 SLR with an 18mm focal length?

Based on my experience, the whole person can be included in the frame at about one and a half meters. As long as a normal person can take a very clear picture. However, if you want to take full-body photos, it is not recommended to use 18mm because it will cause very serious distortion. If the lens is high, the head will be big and the person will be short. If the lens is low, the legs will be long and the head will be small. If the position is just right, you will also gain weight. If the distance allows, you can try 24~35mm, which has less deformation and is more suitable for full-body images. Crop after shooting from a distance of about three meters or more.